Telephony.



1%,844311, PATENTEDTEB. 19, 1907. I. KITSBE. TELEPHONY.

APPLIOATION FILED 00114, 1905.

uanms U TED STATES PATENT OFFICE- ISIDOR KITSEE, OF PIIILAIDELFIIIA, PENNSYLVANIA.

TELEPHONY.

No. 844,811. Specification of Letters Patent.

Patented Feb. 19, 1907. Application filed October 14, 1905. Serial No. 282.817.

T0 Z wZwm it y OOH/667%: I erable in a telephonic system wherein Be 1t known that I, ISIDOR Krrsnn, of the twenty-four volts are employed to make this city and county of Philadelphia and State of resistance of a value ranging from twenty- Pennsylvania, have invented. certain new i five thousand to fifty thousand ohms. The and useful Improvements in Telephony, of latter figure is even preferred to the former; which the following is a specification. this for the twofold reason that the amount My lnvention relates to an improvement of current flowing in this circuit should not in telephony, and has more special reference be sufficient to actuate any of the low-wound to telephonic lines wherein two or more subelectromagnets located at the central stastations are connected in multiple arc. In tion, and for the second reason that the least such a system it often occurs that the subscriber has to remove his receiver from the hook to call up the operator in charge for the purpose of communicating with another sub scriber only to find out that his own line is busy on account of the other party connected thereto using the line. A device, there fore, automatically indicating the condition of such line, if the same is busy or not, would be of great advantage.

My invention, therefore, has for its object to provide such an automatic device to notify the subscriber if his circuit is free or busy.

The accompanying drawing illustrates in diagrammatic view a telephonic line with three substations connected thereto each provided with such means.

1 and 2 are the main lines; a and b, the lines connecting the apparatus of the different stations; 0, the microphonic transmitter; d and e, the two coils of an inductorium; h, a contact-point adapted to contact with the lever 9 when relieved of the receiver f. Thus far the arrangements and devices are the same as are usually employed, but the ringer or bell is omitted, as the connection of the same differs in the various systems of to-day.

The automatic device for indicating the condition of the line is illustrated as embracing the wire Zc, connected to the contact h at one terminal and the electromagnet m at the other terminal. The other terminal of the electromagnet m is connected through the wire Z with the lever g. In proximity to this electromagnet is the lever-armature m, held away from the electromagnet by the spring we and carrying the shield m The movement of this armature is limited by the stops 8 and s, respectively. In proximity to the shield are the two designationssuch, for instance, as the words Busy and l drawing, the circuit for each of the substations A A A is completed as far as conductivity is concerned through this high-resistance electromagnet.

In a twenty-four volt system with, say, four subscribers on the line, and a fifty-thousand-ohm coil for each subscriber, only about one-half of a mill-ampere is used up by each subscribers circuit, which would make in a year less than five amperes, or less than one hundred and twenty watts per subscriber, which would be, figuring on the average cost of electric energy, less than five cents for all four subscribers on the line per year; but it is obvious that the resistance of these coils may differ according to requirements, and accordingly more or less current will flow through the circuit.

The operation of this circuit and device attached thereto is as follows: Normally-that is, when the receiver is on the hookthelever is out of electrical connection with the contact ZL and the circuit is established em bracing wire Z, wire a, microphonic transmitter c, coil (Z, wire Zr, coil ofelectromagnet m, wire Z, wire b, and main line 2. In this condition the electromagnet m is energized,

, circuit, for, as it is clearly illustrated inthe l l shield m toward the stop 8, where y the designation Free is exposed, and as the current divides in accordance with the resistance and each of the substations is of about the same resistance in each of the sub stations will the designation Free be exposed. WVhen, now, one of the subscribers removes his receiver from the hook, the lever 9 will come in electrical connection with the contact h, thereby shunting its own electromagnet m. The armature released from its magnetic pull will be drawn by the spring m in contact with the stop .9, whereby the designation Free will be covered by the l shield m and the designation Busy Will be i exposed, and, as according to the above-cited Freeplaced in such a manner that the shield when covering the one exposes the other, and vice versa.

The coil of the electromagnet m should be of a very high resistance. In fact, it is prefdrawin the armature m with its a ended amount of current should be wasted in such rule the current will seek the path of least resistance, most all of the current through the main wires 1 and 2 will pass through the station having the receiver ofl the hook, and none, or only an insufficient current, will pass through the electromagnets m of the other stations, and the armature m of each of said stations also released from their magnetic pull will be drawn by .the spring m away from the electromagnet m and in contact with the stop 8, thereby covering in each station the designation Free and exposing at each station the designation Busy, thereby notiiying each of the subscribers connected to this line the condition of the wire.

It is obvious that the device may be placed on the portable or stationary phone or may be secured at any desired point separate therefrom.

If it is desired, the electromagnet m may also .be used for ringing-up purposes. In this case the usual bell and clapper has to be added but I do not deem it necessary to illustrate this arrangement here, as the use of bells and clappers are well understood and may differ according to requirements.

Having now described my invention, what I claim as new, and desire to secure by Let ters Patent, is-

A telephonic line having a series of substations connected thereto in multiple arc, an electromagnetic resistance in series with the circuit of each of said stations, means to short-circuit said resistance by the removal of the receiver from its hook, an armature I for each of said electromagnetic resistances, and a signal in operative relation to said armature.

In testimony whereof I affiX my signature in presence of two witnesses.

ISIDOR KITSEE.

Witnesses EDITH R. STILL Y, ALVAH RITTENHOUSE. 

